We can visit gyms after level 5, and presumably fight against the local pokemon which will actually be the first time fighting (so far, I have only collected pokemon, if there are fights pre-L5 please tell me how).
All of my freshly caught Pokemon are unevolved and none of the obtained candies have been used. They are also a mix of various types, with 1 Psychic type (Abra) which afaik is strong vs almost all types?
Do I need to evolve one or more pokemon first, or create teams from specific types (not played much of the regular Pokemon series)? Are there benefits to 'gym challenges' even if I don't win, or should I wait until I have a strong team to attempt them?